The present invention relates to a radiation-resistant silica glass optical conductor, such as an optical fiber for telecommunication, a multiple fiber for an image scope, and a light guide for illumination.
It has been proposed or tried to use an optical conductor as a means for telecommunication, measurement, and control in the sites where it is possible to receive harmful irradiation, such as an atomic pile, an atomic ship, an artificial satellite and the like.
In general, optical conductors consist of a core through which optical energy or signals pass, and a cladding layer formed on the core. Multi-mode optical conductors have a very thin cladding layer of several micron meter order, because the optical energy escapes hardly from the core into the cladding layer as compared with the case of single-mode optical conductors. Multi-mode optical conductors, however, will increase markedly their optical transmission loss when received irradiation, such as gamma rays, X-rays etc.
It is well-known that silica glass optical conductors have excellent radiation resistance as compared with multi-component glass optical conductors. According to the studies of the present inventors, however, the radiation resistance of the silica glass optical conductors are various, and are varied by the material which composes of the core or the cladding layer.